Pushrod Clearance - How Tight is Too Tight?

[Blown&Injected]

A .020 shim will clear and I believe the MFR says .010 is all that is needed, but man that is tight.

Any experiences that might sooth my mind?

Thanks

 

[chrisgarrett]

Are you talking about preload?

 

[Blown&Injected]

No. I mean the clearance between the head and the pushrod.

After reading about the Spintron testing and having to go back in my motor and because of a lifter change needing slightly longer pushrods I decided to try some bigger pushrods.

All the charts say 5/16 is fine for even the roller cam spring pressures we run in the TR's but WTH - had to go in anyway and all the PR guru's say that the slightly heavier rod is not important because it is on the slower moving side of the valve system